Automatically actuated door arrangements have been known and used in the past. Typically, these devices have relied on the application of a physical force to mechanically slide open the doors, as in U.S. Pat. No. 4,411,102. Others utilize swinging doors which pivot outward, as in U.S. Pat. No. 4,442,630. Still others utilize magnetic materials to actuate movement of the doors, as in U.S. Pat. No. 4,674,231.
However, problems have been encountered with certain aspects of prior art devices. Particularly, none of the prior art devices provide for a fully automatic sliding door arrangement which is actuated without the application of a physical force input by the operator. The prior art devices all require a physical input by the operator. The prior art devices all require a physical input to actuate the door-opening movement. The necessity of a physical input detracts from the ability of the operator to perform other tasks, such as serving merchandise to customers and receiving payment through the door arrangement. Also, the speed and manner of door operation all affect the efficiency of the operator's actions. Factors such as speed of doors opening, opening sizes, and door sealing ability have been problematic in prior arrangements. Doors which stick open, or fail to close entirely, give rise to an uncomfortable and inefficient working environment for the operator, particularly in inclement weather. Also, because prior arrangements lack mechanisms for the detection of malfunctions, problem diagnosis in the past has been difficult.